Search results
Results From The WOW.Com Content Network
Phosphorus has several allotropes that exhibit strikingly diverse properties. [11] The two most common allotropes are white phosphorus and red phosphorus. [12] For both pure and applied uses, the most important allotrope is white phosphorus, often abbreviated WP. White phosphorus is a soft, waxy molecular solid composed of P 4 tetrahedra. This P
White phosphorus, yellow phosphorus or simply tetraphosphorus (P 4) exists as molecules of four phosphorus atoms in a tetrahedral structure, joined by six phosphorus—phosphorus single bonds. [1] The free P 4 molecule in the gas phase has a P-P bond length of r g = 2.1994(3) Å as was determined by gas electron diffraction . [ 2 ]
The phosphate ion has a molar mass of 94.97 g/mol, and consists of a central phosphorus atom surrounded by four oxygen atoms in a tetrahedral arrangement. It is the conjugate base of the hydrogen phosphate ion H(PO 4) 2−, which in turn is the conjugate base of the dihydrogen phosphate ion H 2 (PO 4) −
Element Negative states Positive states Group Notes −5 −4 −3 −2 −1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 Z; 1 hydrogen: H −1 +1: 1 2 helium: He 0 18
The reduced metal can be observed as a visible darkening of the phosphor layer. The darkening (and the brightness loss) is proportional to the phosphor's exposure to electrons and can be observed on some CRT screens that displayed the same image (e.g. a terminal login screen) for prolonged periods. [14]
The acid is prepared industrially via a two step process: Firstly, elemental white phosphorus reacts with alkali and alkaline earth hydroxides to give an aqueous solution of hypophosphites: P 4 + 4 OH − + 4 H 2 O → 4 H 2 PO − 2 + 2 H 2. Any phosphites produced in this step can be selectively precipitated out by treatment with calcium salts.
The first practical use of molecular graphics was a simple display of the protein myoglobin using a wireframe representation in 1966 by Cyrus Levinthal and Robert Langridge working at Project MAC. [7] Among the milestones in high-performance molecular graphics was the work of Nelson Max in "realistic" rendering of macromolecules using ...
Dicalcium phosphate is the calcium phosphate with the formula CaHPO 4 and its dihydrate. The "di" prefix in the common name arises because the formation of the HPO 4 2– anion involves the removal of two protons from phosphoric acid, H 3 PO 4.